Muricauda flavescens sp. nov. and Muricauda aquimarina sp. nov., isolated from a salt lake near Hwajinpo Beach of the East Sea in Korea, and emended description of the genus Muricauda

Abstract

Four Gram-negative, non-spore-forming, slightly halophilic rods (strains SW-62T, SW-74, SW-63T and SW-72) with appendages were isolated from a salt lake near Hwajinpo Beach on the East Sea in Korea, and subjected to a polyphasic taxonomic analysis. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-62T, SW-74, SW-63T and SW-72 formed a coherent cluster with Muricauda ruestringensis. Strains SW-62T and SW-74 had the same 16S rRNA gene sequence, as did strains SW-63T and SW-72. The level of 16S rRNA gene sequence similarity between strains SW-62T and SW-63T was 97·0 %. Strains SW-62T and SW-63T exhibited 16S rRNA gene similarity levels of 96·5 and 98·3 %, respectively, with respect to M. ruestringensis DSM 13258T. The predominant isoprenoid quinone found in the four isolates and M. ruestringensis DSM 13258T was MK-6. The four strains contained iso-C17 : 0 3-OH, iso-C15 : 1 and iso-C15 : 0 as the major fatty acids. Their DNA G+C contents were 44·1–45·4 mol%. The levels of DNA–DNA relatedness indicated that strains SW-62T and SW-74 and strains SW-63T and SW-72 were members of two species that were different from M. ruestringensis. On the basis of phenotypic and phylogenetic data and genomic distinctiveness, strains SW-62T and SW-74 and strains SW-63T and SW-72 were placed in the genus Muricauda as two distinct novel species, for which the names Muricauda flavescens sp. nov. (type strain, SW-62T=KCCM 41645T=JCM 11812T) and Muricauda aquimarina sp. nov. (type strain, SW-63T=KCCM 41646T=JCM 11811T), respectively, are proposed.